I'm not sure this is an emergency, but...

This is a discussion on I'm not sure this is an emergency, but... within the Tropical Fish Diseases forums, part of the Freshwater Fish and Aquariums category; -->
I really need to find a solution.
I've got a 20gal tall tank, Fluval canister filter 104 (?) I believe?
3 Giant Danios - ...

3 Giant Danios - who are the meekest fish in the tank, even though they're the biggest
3 Green Tiger Barbs - the newest additions
1 Rainbow Shark - it's his tank, anyone who doesn't like it can leave

About 2 weeks ago, I noticed that one of the barbs (they're still small - about 1.5") has lost most of its dorsal fin to the shark. It seems that the shark has decided that about a third of the tank, where its cave is, is off limits to anything else and chases them like mad. I've seen it catch the barb and keep nipping it. The shark has always enjoyed chasing other fish from time to time but this is insane. It happens constantly, the only break being during feeding. Is there any way to fix this problem without moving any of the fish to another tank? This fish is starting to get pretty beat up, while the others are getting away. Is it just natural selection?

well, in the wild i would call it natural selection...but as far as your conditions go, i might call it animal abuse, considering that you probably know that your shark is aggressive, and that the other fish wont stand up to it, and you have seen it tearing up one of your barbs.

why wouldnt you rehome the barbs so they dont die? it seems cruel to me that you would allow these fish to be tormented like that...they depend completely on your for their tank conditions and survival. there is no solution to this problem other than the obvious one. either the barbs need to go, or the shark. but if you continue to ignore the fact that these fish shouldn't be kept together, then they will die.

you should research the fish that you have and what the best possible tank-mates would be according to his disposition. then you will not have wasted your money on fish that will get eaten, and those fish can go live happily in someone else's tank.

The shark has never actually nipped any of the other fish at all. None of the danios, sparkling gourami, catfish, shrimp, or other barbs has ever been nipped. The shark has chased all of them though. This is literally the only fish that it's gone after like this. Maybe I'm personifying it too much, but is it possible it just doesn't like this one fish?

The sites I've looked at all have given tiger barbs as possible tankmates of rainbow sharks. Websites as well as the 2 people who work at the pet store I shop at too. Usually, sharks stay on the bottom of the tank while the barbs occupy the middle/top.

Thanks for throwing me under the bus without being fully informed though.

i was not intending to "throw you under the bus". i was just giving you my opinion. and you cant always trust what the people at the lfs tell you, because most of the time they were hired to sell fish, and are not educated about them first.

and your list of fish didnt say anything about gourami, catfish or shrimp.

found this bit of info on another site:

Quote:

Usually, Rainbow Sharks remain in the middle to bottom levels of aquariums. Most do not tolerate other Rainbow Sharks and must be kept singly. If other fish are present in the tank, they should be of roughly equal size and temperament to the Rainbow Shark in order to avoid stress and bullying. The Rainbow Shark is quite territorial, and decorations in its enclosure will help it to create territorial boundaries. Despite its tendencies to eat smaller fish, the Rainbow Shark is in essence a type of algae eating minnow, not of the shark family.

I didn't list the other fish as they are no longer in that tank. I moved them to a 5 gallon or gave them away. I know that I can't always trust the fish people but at this store, they have always given me good advice, backed up by web research.

Thanks for the quote about the shark. I wonder if it's because the barb it goes after is the smallest one. There are plenty of decorations - all live - and the fish only get chased when they near the cave. This one just likes to hang out in that corner so it gets chased a lot. That's why I was calling it natural selection...not that fish are known for their intelligence.

Other than removing the fish - since I would have to remove all 3 of the barbs, is there anything I can do? Rearrange the tank maybe?

Quote:

Originally Posted by girlofgod

i was not intending to "throw you under the bus". i was just giving you my opinion. and you cant always trust what the people at the lfs tell you, because most of the time they were hired to sell fish, and are not educated about them first.

and your list of fish didnt say anything about gourami, catfish or shrimp.

found this bit of info on another site:

Quote:

Usually, Rainbow Sharks remain in the middle to bottom levels of aquariums. Most do not tolerate other Rainbow Sharks and must be kept singly. If other fish are present in the tank, they should be of roughly equal size and temperament to the Rainbow Shark in order to avoid stress and bullying. The Rainbow Shark is quite territorial, and decorations in its enclosure will help it to create territorial boundaries. Despite its tendencies to eat smaller fish, the Rainbow Shark is in essence a type of algae eating minnow, not of the shark family.

i'm not quite sure...you might try upgrading to a larger tank so there is more room for the shark to pick his territory and the barbs to stay out of his way. other than that...sorry. hope you figure it out! good luck!

20 gallons is far too small for RTBS. They will need well-defined territories and in a 20 gallons tank, they will only attack their tankmates. IMO, one labeo will need 40 gallons as the minimum. In a 20 gallons tank, I wouldn't keep other fish with a labeo.

It is best to replace your labeo with other alternatives. Otherwise, you have to upgrade the tank as Bri mentioned.

On the contrary, labeos can grow to almost 6 inches and it is still a bad idea to buy other fish reaching that size since the tank is only 20 gallons.

I had a red-tailed shark that killed my other fish -- he was maybe 2 inches and he chased harlequin rasboras to death. I didn't know at the time, I thought they were dying of disease/water conditions (I had like 6 and each day one was dead). Then I caught him in the act chasing the last 2 -- I immediately realized what had been happening and moved the rasboras. They are still alive over a year later.

I've had tiger barbs in the past, and no offensive to anyone, but I don't know how anyone can stand these punks! These guys tended to harass each other and anyone else in the tank.

I think having a mix of bully type fish is the problem -- I don't know for sure, but I would wonder if your tiger barb isn't the one that occasionally starts the conflict with your rainbow shark.

Your tiger barb will likely die due to stress. Then it is very likely your rainbow will start to harass somebody else.

I've had tiger barbs in the past, and no offensive to anyone, but I don't know how anyone can stand these punks! These guys tended to harass each other and anyone else in the tank.

Right. They will bully other fish if kept in less number. 8 or more would be the option so they can form a hierarchy among themselves and will not bother others in the process.
Keep them in less than 6 and see what you get. They will nip other fish and this will also apply to being cramped in a small tank. Even 8 of them in a small tank will not work(except in large tanks) as they are being cramped for space which will most likely give them the chance to bully other fish.

IMO, I wouldn't even mix tiger barbs with fish having long fins especially in a very large tank. No matter how large the tank you have, they will always try to nip fish with very long fins. Long fins are quite tempting to them.